:root{
  color-scheme: light;
  --bg:#F4F7FC; --bg2:#EAF0FA; --surface:#FFFFFF; --ink:#0E1A33; --ink2:#2A3856; --muted:#5B688A; --line:#DFE7F3; --line2:#CBD6E8;
  --blue:#2A5BD7; --blue-d:#1B3F9E; --blue-t:#E7EEFF; --blue-t2:#D3E0FF;
  --sun:#FFC83A; --sun-d:#B98500; --sun-t:#FFF3CC;
  --mint:#0F9F77; --mint-t:#DDF6EC; --coral:#E24A4F; --coral-t:#FCE8E9;
  --code-bg:#0F1B36; --code-ink:#DCE6FF; --code-dim:#7C8CB3;
  --t-for:#2A5BD7; --t-cond:#E8801C; --t-range:#0B95A3; --t-list:#2E9E58; --t-tuple:#7B57E8; --t-dict:#D93F7A; --t-set:#B98500; --t-types:#8A5A44; --t-typing:#5B6CFF; --t-vars:#C2410C; --t-func:#0E7490; --t-mut:#BE185D; --t-run:#4D7C0F; --t-env:#6D28D9;
  --r:14px; --shadow:0 1px 2px rgba(14,26,51,.05),0 8px 24px rgba(14,26,51,.06); --shadow2:0 2px 4px rgba(14,26,51,.06),0 18px 40px rgba(14,26,51,.10);
  --display:'Bricolage Grotesque','Trebuchet MS','Segoe UI',system-ui,sans-serif;
  --body:'Figtree','Segoe UI',system-ui,-apple-system,sans-serif;
  --mono:'JetBrains Mono',ui-monospace,'SFMono-Regular',Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 var(--body);-webkit-font-smoothing:antialiased;overflow-x:hidden}
h1,h2,h3,h4{font-family:var(--display);line-height:1.12;margin:0;letter-spacing:-.02em;text-wrap:balance}
p{margin:0}
a{color:var(--blue)}
button{font:inherit;color:inherit;cursor:pointer}
code{font-family:var(--mono);font-size:.88em;background:var(--blue-t);color:var(--blue-d);padding:.08em .38em;border-radius:6px}
:focus-visible{outline:3px solid var(--sun);outline-offset:2px;border-radius:6px}
.wrap{max-width:1180px;margin:0 auto;padding-inline:20px}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}

/* ---------- top nav ---------- */
.nav{position:sticky;top:env(safe-area-inset-top,0px);z-index:50;background:rgba(244,247,252,.86);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
.nav .wrap{display:flex;align-items:center;gap:16px;height:62px}
.brand{display:flex;align-items:center;gap:10px;font-family:var(--display);font-weight:800;font-size:1.08rem;letter-spacing:-.02em;color:var(--ink);text-decoration:none;white-space:nowrap;cursor:pointer;background:none;border:0;padding:0}
.logo{width:34px;height:34px;border-radius:10px;background:var(--blue);display:grid;place-items:center;position:relative;box-shadow:0 4px 12px rgba(42,91,215,.35)}
.logo::before{content:'';position:absolute;right:-3px;bottom:-3px;width:14px;height:14px;background:var(--sun);border-radius:5px;z-index:0}
.logo span{position:relative;z-index:1;color:#fff;font:700 13px var(--mono)}
.links{display:flex;gap:4px;margin-left:auto;overflow-x:auto;scrollbar-width:none}
.links::-webkit-scrollbar{display:none}
.links button{background:none;border:0;padding:8px 14px;border-radius:999px;font-weight:600;color:var(--ink2);white-space:nowrap;transition:background .2s,color .2s}
.links button:hover{background:var(--bg2)}
.links button.on{background:var(--ink);color:#fff}

/* ---------- generic ---------- */
main{min-height:70vh}
.lab>*,.ws>*,.walk>*,.hero-grid>*,.two>*,.band>*{min-width:0}

.view{animation:rise .45s cubic-bezier(.2,.7,.2,1) both}
@keyframes rise{from{opacity:0;transform:translateY(14px)}to{opacity:1;transform:none}}
.eyebrow{font:700 .74rem var(--body);letter-spacing:.14em;text-transform:uppercase;color:var(--blue)}
.btn{display:inline-flex;align-items:center;gap:8px;border:0;border-radius:12px;padding:12px 20px;font-weight:700;background:var(--surface);color:var(--ink);box-shadow:inset 0 0 0 1.5px var(--line2);transition:transform .15s,box-shadow .2s,background .2s;text-decoration:none}
.btn:hover{transform:translateY(-2px);box-shadow:inset 0 0 0 1.5px var(--blue),0 8px 18px rgba(42,91,215,.14)}
.btn:active{transform:translateY(0) scale(.98)}
.btn.primary{background:var(--blue);color:#fff;box-shadow:0 8px 20px rgba(42,91,215,.32)}
.btn.primary:hover{background:var(--blue-d);box-shadow:0 12px 26px rgba(42,91,215,.4)}
.btn.sun{background:var(--sun);color:#3a2a00;box-shadow:0 8px 20px rgba(255,200,58,.4)}
.btn.sm{padding:8px 14px;border-radius:10px;font-size:.9rem}
.btn[disabled]{opacity:.5;pointer-events:none}
.pill{display:inline-flex;align-items:center;gap:6px;font-size:.76rem;font-weight:700;padding:3px 10px;border-radius:999px;background:var(--blue-t);color:var(--blue-d)}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--shadow)}
.ttl-sec{font-size:clamp(1.6rem,3.2vw,2.3rem);font-weight:800}

/* ---------- landing ---------- */
.hero{position:relative;overflow:hidden;padding-block:56px 40px}
.hero::before{content:'';position:absolute;inset:0;background-image:radial-gradient(var(--line2) 1.2px,transparent 1.4px);background-size:26px 26px;opacity:.55;mask-image:linear-gradient(180deg,#000 0%,transparent 85%);-webkit-mask-image:linear-gradient(180deg,#000 0%,transparent 85%)}
.blob{position:absolute;border-radius:50%;filter:blur(60px);opacity:.5;animation:drift 14s ease-in-out infinite alternate}
.blob.b1{width:340px;height:340px;background:#BBD0FF;right:-60px;top:-40px}
.blob.b2{width:260px;height:260px;background:#FFE9A6;left:-70px;bottom:-40px;animation-delay:-6s}
@keyframes drift{to{transform:translate(30px,26px) scale(1.12)}}
.hero-grid{position:relative;display:grid;grid-template-columns:1.05fr .95fr;gap:44px;align-items:center}
.hero h1{font-size:clamp(2.5rem,6vw,4.4rem);font-weight:800;margin:14px 0 18px}
.hero h1 em{font-style:normal;color:var(--blue);position:relative;white-space:nowrap}
.hero h1 em::after{content:'';position:absolute;left:-2%;right:-2%;bottom:.04em;height:.24em;background:var(--sun);z-index:-1;border-radius:4px;transform-origin:left;animation:underline 1s .5s cubic-bezier(.2,.8,.2,1) both}
@keyframes underline{from{transform:scaleX(0)}}
.lead{font-size:1.16rem;color:var(--ink2);max-width:34em}
.cta{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}
.chips-row{display:flex;flex-wrap:wrap;gap:8px;margin-top:26px}
.tchip{font:600 .82rem var(--mono);padding:5px 11px;border-radius:9px;background:var(--surface);border:1px solid var(--line);color:var(--ink2);cursor:pointer;transition:transform .2s,border-color .2s,color .2s}
.tchip:hover{transform:translateY(-3px) rotate(-1.5deg);border-color:var(--c,var(--blue));color:var(--c,var(--blue))}
.demo{position:relative}
.term{background:var(--code-bg);border-radius:18px;box-shadow:var(--shadow2);overflow:hidden;color:var(--code-ink)}
.term-bar{display:flex;align-items:center;gap:7px;padding:11px 14px;background:rgba(255,255,255,.05);font:600 .78rem var(--mono);color:var(--code-dim)}
.dot{width:11px;height:11px;border-radius:50%}
.term pre{margin:0;padding:18px 20px;font:500 .95rem/1.75 var(--mono);white-space:pre;overflow-x:auto;min-height:170px}
.term .out{border-top:1px dashed rgba(255,255,255,.16);padding:12px 20px 16px;font:500 .9rem/1.6 var(--mono);color:#8DF0C6;min-height:112px}
.caret{display:inline-block;width:8px;height:1.1em;background:var(--sun);vertical-align:-.2em;animation:blink 1s steps(2) infinite}
@keyframes blink{50%{opacity:0}}
.float-tag{position:absolute;font:700 .8rem var(--mono);padding:6px 11px;border-radius:10px;background:var(--surface);box-shadow:var(--shadow2);border:1px solid var(--line);animation:bob 5s ease-in-out infinite}
.float-tag.f1{right:-8px;top:-18px;color:var(--t-range)}
.float-tag.f2{left:34px;bottom:-24px;color:var(--t-dict);animation-delay:-2s}
.float-tag.f3{right:22px;bottom:-20px;color:var(--t-set);animation-delay:-3.5s}
@keyframes bob{50%{transform:translateY(-9px)}}
.sec{padding-block:54px}
.sec-head{max-width:40em;margin-bottom:28px}
.sec-head p{color:var(--muted);margin-top:10px;font-size:1.05rem}
.pillars{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.pillar{padding:26px;position:relative;overflow:hidden;transition:transform .25s,box-shadow .25s;cursor:pointer;text-align:left;font:inherit}
.pillar:hover{transform:translateY(-6px);box-shadow:var(--shadow2)}
.pillar .ic{width:52px;height:52px;border-radius:14px;display:grid;place-items:center;margin-bottom:16px}
.pillar h3{font-size:1.35rem;margin-bottom:8px}
.pillar p{color:var(--muted)}
.pillar .go{margin-top:16px;font-weight:700;color:var(--blue);display:inline-flex;gap:6px;align-items:center}
.pillar .go i{transition:transform .2s;font-style:normal}
.pillar:hover .go i{transform:translateX(5px)}
.topics{display:grid;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:14px}
.topic{padding:18px;border-radius:var(--r);background:var(--surface);border:1px solid var(--line);cursor:pointer;text-align:left;transition:transform .25s,box-shadow .25s,border-color .25s;position:relative;overflow:hidden}
.topic:hover{transform:translateY(-5px);box-shadow:var(--shadow2);border-color:var(--c)}
.topic .sym{font:800 1.5rem var(--mono);color:var(--c);display:block;margin-bottom:10px;transition:transform .3s}
.topic:hover .sym{transform:scale(1.15) rotate(-4deg)}
.topic b{display:block;font-family:var(--display);font-size:1.05rem}
.topic small{color:var(--muted)}
.band{background:var(--ink);color:#fff;border-radius:22px;padding:34px;display:grid;grid-template-columns:1.2fr 1fr;gap:26px;align-items:center;overflow:hidden;position:relative}
.band h2{font-size:clamp(1.5rem,3vw,2.1rem)}
.band p{color:#B9C6E6;margin-top:10px}
.flow{display:flex;gap:8px;flex-wrap:wrap;align-items:center;font:600 .82rem var(--mono)}
.flow span{padding:8px 12px;border-radius:10px;background:rgba(255,255,255,.09);animation:pulse 3.6s infinite}
.flow span:nth-child(3){animation-delay:.6s}.flow span:nth-child(5){animation-delay:1.2s}.flow span:nth-child(7){animation-delay:1.8s}
.flow i{font-style:normal;color:var(--sun)}
@keyframes pulse{0%,100%{background:rgba(255,255,255,.09)}18%{background:rgba(255,200,58,.35)}}
.foot{border-top:1px solid var(--line);padding-block:26px;color:var(--muted);font-size:.9rem;margin-top:30px}

/* ---------- section header ---------- */
.page-head{padding-block:38px 20px}
.page-head p{color:var(--muted);max-width:44em;margin-top:8px}

/* ---------- concept lab ---------- */
.lab-tabs{display:flex;gap:8px;overflow-x:auto;padding-bottom:6px;scrollbar-width:thin}
.lab-tab{flex:0 0 auto;display:flex;align-items:center;gap:8px;padding:9px 15px;border-radius:12px;border:1.5px solid var(--line);background:var(--surface);font-weight:700;transition:all .2s}
.lab-tab i{font:800 .95rem var(--mono);font-style:normal;color:var(--c)}
.lab-tab:hover{border-color:var(--c)}
.lab-tab.on{background:var(--c);border-color:var(--c);color:#fff}
.lab-tab.on i{color:#fff}
.lab{margin-top:16px;display:grid;grid-template-columns:1.9fr 1fr;gap:18px;align-items:start}
.lab-main{padding:22px}
.lab-side{padding:22px}
.lab-side h3{font-size:1.2rem;margin-bottom:10px}
.lab-side ul{padding-left:18px;margin:0 0 16px;color:var(--ink2)}
.lab-side li{margin-bottom:8px}
.snippet{background:var(--code-bg);color:var(--code-ink);border-radius:12px;padding:14px 16px;font:500 .9rem/1.7 var(--mono);overflow-x:auto;white-space:pre}
.snippet .ln{display:block;padding:0 8px;margin:0 -8px;border-radius:6px;transition:background .25s}
.snippet .ln.act{background:rgba(255,200,58,.22);box-shadow:inset 3px 0 0 var(--sun)}
.ctl{display:flex;flex-wrap:wrap;gap:14px 22px;align-items:end;margin-bottom:16px}
.ctl label{display:flex;flex-direction:column;gap:4px;font:700 .78rem var(--body);color:var(--muted);text-transform:uppercase;letter-spacing:.08em}
.ctl label b{font:700 1.1rem var(--mono);color:var(--ink);text-transform:none;letter-spacing:0}
input[type=range]{accent-color:var(--blue);width:160px;max-width:100%}
.field{font:600 .95rem var(--mono);padding:8px 10px;border-radius:9px;border:1.5px solid var(--line2);background:#fff;color:var(--ink);width:110px;max-width:100%}
.field:focus{border-color:var(--blue);outline:none;box-shadow:0 0 0 3px var(--blue-t2)}
.seg{display:inline-flex;background:var(--bg2);border-radius:11px;padding:3px;gap:2px}
.seg button{border:0;background:none;padding:7px 13px;border-radius:9px;font-weight:700;font-size:.88rem;color:var(--muted);transition:all .2s}
.seg button.on{background:#fff;color:var(--ink);box-shadow:0 1px 4px rgba(14,26,51,.14)}
.hint-note{font-size:.9rem;color:var(--muted);margin-top:12px}
.ops{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:14px}
.op{font:600 .82rem var(--mono);padding:7px 11px;border-radius:9px;border:1.5px solid var(--line2);background:#fff;transition:all .18s}
.op:hover{border-color:var(--blue);color:var(--blue);transform:translateY(-2px)}
.op.on{background:var(--blue);border-color:var(--blue);color:#fff}
.console-mini{white-space:pre-wrap;word-break:break-word;font:600 .9rem var(--mono);background:var(--code-bg);color:#8DF0C6;border-radius:10px;padding:10px 14px;min-height:44px;margin-top:12px;overflow-x:auto}
.console-mini.err{color:#FF9DA1}
/* range strip */
.strip{display:flex;gap:4px;overflow-x:auto;padding:26px 4px 10px;position:relative}
.cell{flex:0 0 38px;height:46px;border-radius:9px;background:var(--bg2);border:1.5px solid var(--line);display:grid;place-items:center;font:700 .85rem var(--mono);color:var(--muted);position:relative;transition:transform .3s,background .3s,color .3s}
.cell.in{background:var(--blue);border-color:var(--blue);color:#fff;transform:translateY(-4px);animation:pop .4s both}
.cell.now{background:var(--sun);border-color:var(--sun);color:#3a2a00;transform:translateY(-10px) scale(1.12);box-shadow:0 8px 16px rgba(255,200,58,.5)}
.cell.zero{border-bottom:4px solid var(--ink2)}
.cell .tag{position:absolute;top:-22px;left:50%;transform:translateX(-50%);font:700 .64rem var(--body);text-transform:uppercase;letter-spacing:.06em;white-space:nowrap;color:var(--coral)}
.cell.st{outline:2px dashed var(--mint);outline-offset:2px}
.cell.st .tag{color:var(--mint)}
.cell.sp{outline:2px dashed var(--coral);outline-offset:2px}
.cell.sp .tag{color:var(--coral)}
@keyframes pop{0%{transform:scale(.5)}70%{transform:translateY(-4px) scale(1.1)}}
.vals{display:flex;flex-wrap:wrap;gap:6px;margin-top:12px;min-height:38px}
.chip{font:700 .88rem var(--mono);padding:5px 11px;border-radius:9px;background:var(--blue-t);color:var(--blue-d);animation:pop .35s both}
/* loop stepper */
.conv{display:flex;gap:10px;margin:14px 0;flex-wrap:wrap}
.item{min-width:56px;padding:12px 14px;border-radius:12px;background:var(--bg2);border:2px solid var(--line);font:700 1rem var(--mono);text-align:center;transition:all .35s;position:relative}
.item.done{opacity:.45;transform:scale(.94)}
.item.cur{background:var(--sun);border-color:var(--sun);transform:translateY(-8px) scale(1.08);box-shadow:0 12px 20px rgba(255,200,58,.45)}
.item.cur::after{content:'▼';position:absolute;top:-22px;left:50%;transform:translateX(-50%);font-size:.7rem;color:var(--sun-d)}
.vars{display:flex;gap:12px;flex-wrap:wrap;margin:8px 0}
.vbox{background:#fff;border:1.5px solid var(--line2);border-radius:12px;padding:8px 14px;min-width:96px}
.vbox small{display:block;font:700 .7rem var(--body);color:var(--muted);text-transform:uppercase;letter-spacing:.08em}
.vbox b{font:700 1.15rem var(--mono);color:var(--ink)}
.vbox.bump{animation:bump .45s}
@keyframes bump{40%{transform:scale(1.14);border-color:var(--blue);background:var(--blue-t)}}
.note{background:var(--sun-t);border-radius:11px;padding:10px 14px;font-weight:600;color:#5b4300;min-height:44px}
/* if lab */
.branch{display:grid;grid-template-columns:26px 1fr auto;gap:12px;align-items:center;padding:11px 14px;border-radius:12px;border:1.5px solid var(--line);background:#fff;margin-bottom:9px;transition:all .3s;opacity:.38;transform:translateX(-8px)}
.branch.show{opacity:1;transform:none}
.branch code{background:none;padding:0;color:var(--ink);font-weight:600}
.branch .st{font:700 .78rem var(--body);padding:3px 10px;border-radius:999px}
.branch.t{border-color:var(--mint);background:var(--mint-t)}
.branch.t .st{background:var(--mint);color:#fff}
.branch.f .st{background:var(--coral-t);color:var(--coral)}
.branch.sk{opacity:.4;background:var(--bg2)}
.branch.sk .st{background:var(--line);color:var(--muted)}
.mark{width:22px;height:22px;border-radius:50%;display:grid;place-items:center;font:800 .75rem var(--body);background:var(--line);color:var(--muted)}
.t .mark{background:var(--mint);color:#fff}.f .mark{background:var(--coral);color:#fff}
.bigout{font:800 1.5rem var(--mono);margin-top:8px}
.bigout span{display:inline-block;background:var(--blue);color:#fff;padding:2px 14px;border-radius:10px;animation:pop .45s both}
/* list lab */
.lbox-row{display:flex;gap:8px;flex-wrap:wrap;padding:30px 0 34px}
.lbox{position:relative;min-width:62px;height:56px;border-radius:12px;background:var(--blue-t);border:2px solid var(--blue);display:grid;place-items:center;font:700 .95rem var(--mono);color:var(--blue-d);transition:all .3s}
.lbox .ix{position:absolute;top:-22px;left:50%;transform:translateX(-50%);font:700 .72rem var(--mono);color:var(--muted)}
.lbox .nx{position:absolute;bottom:-24px;left:50%;transform:translateX(-50%);font:700 .72rem var(--mono);color:var(--coral)}
.lbox.new{animation:pop .45s both}
.lbox.leave{animation:leave .28s forwards}
.lbox.sel{background:var(--sun);border-color:var(--sun-d);color:#3a2a00;transform:translateY(-6px)}
@keyframes leave{to{transform:scale(.3) translateY(-14px);opacity:0}}
/* tuple lab */
.two{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.pane{border:1.5px solid var(--line);border-radius:14px;padding:16px;background:#fff}
.pane h4{font-size:1rem;margin-bottom:12px;display:flex;align-items:center;gap:8px}
.pane.shake{animation:shake .5s}
@keyframes shake{20%,60%{transform:translateX(-8px)}40%,80%{transform:translateX(8px)}}
.lock{font-size:.72rem;font-weight:800;background:var(--coral-t);color:var(--coral);padding:2px 8px;border-radius:999px}
.unlock{font-size:.72rem;font-weight:800;background:var(--mint-t);color:var(--mint);padding:2px 8px;border-radius:999px}
.swapline{display:flex;gap:16px;align-items:center;flex-wrap:wrap;margin-top:12px}
.vslot{width:84px;height:64px;border-radius:12px;border:2px dashed var(--line2);display:grid;place-items:center;position:relative;transition:transform .6s cubic-bezier(.6,-.2,.3,1.2),background .3s}
.vslot small{position:absolute;top:-10px;left:8px;background:var(--bg);padding:0 6px;font:700 .72rem var(--mono);color:var(--muted)}
.vslot b{font:800 1.2rem var(--mono);color:var(--blue-d)}
.vslot.filled{border-style:solid;border-color:var(--blue);background:var(--blue-t)}
/* dict lab */
.dcards{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:10px;margin:8px 0 14px}
.dcard{border:1.5px solid var(--line2);border-radius:12px;background:#fff;overflow:hidden;position:relative;animation:pop .4s both;transition:box-shadow .3s,transform .3s}
.dcard .k{background:var(--t-dict);color:#fff;font:700 .82rem var(--mono);padding:5px 10px;display:flex;justify-content:space-between;gap:6px}
.dcard .k button{background:none;border:0;color:#fff;opacity:.75;padding:0 2px;font-weight:800}
.dcard .k button:hover{opacity:1}
.dcard .v{padding:10px;font:700 1rem var(--mono);word-break:break-all}
.dcard.hit{box-shadow:0 0 0 3px var(--sun);transform:translateY(-4px)}
.dcard.leave{animation:leave .28s forwards}
.row-in{display:flex;gap:8px;flex-wrap:wrap;align-items:center;margin-bottom:10px}
/* set lab */
.venn{position:relative;width:100%;max-width:560px;aspect-ratio:1.667;margin:6px auto 12px}
.circ{position:absolute;top:0;width:60%;aspect-ratio:1;border-radius:50%;transition:opacity .3s}
.circ.a{left:0;background:rgba(42,91,215,.16);border:2px solid var(--blue)}
.circ.b{right:0;background:rgba(255,200,58,.28);border:2px solid var(--sun-d)}
.zones{position:absolute;inset:0;display:grid;grid-template-columns:40% 20% 40%;align-items:center}
.zone{display:flex;flex-wrap:wrap;gap:6px;justify-content:center;align-content:center;padding:4px;min-height:60px}
.zn{position:absolute;bottom:-4px;font:800 .72rem var(--body);letter-spacing:.08em;text-transform:uppercase}
.sch{font:700 .9rem var(--mono);padding:5px 10px;border-radius:999px;background:#fff;border:1.5px solid var(--line2);cursor:pointer;transition:all .3s;animation:pop .35s both}
.sch:hover{border-color:var(--coral);color:var(--coral)}
.sch.hl{background:var(--ink);color:#fff;border-color:var(--ink);transform:scale(1.15);box-shadow:0 8px 16px rgba(14,26,51,.25)}
.sch.dim{opacity:.35}

/* ---------- practice list ---------- */
.prog{display:flex;align-items:center;gap:14px;padding:12px 18px;background:var(--surface);border:1px solid var(--line);border-radius:16px}
.ring{--p:0;width:54px;height:54px;border-radius:50%;background:conic-gradient(var(--mint) calc(var(--p)*1%),var(--line) 0);display:grid;place-items:center;transition:background .6s}
.ring::before{content:'';width:42px;height:42px;background:var(--surface);border-radius:50%;grid-area:1/1}
.ring b{grid-area:1/1;font:800 .82rem var(--mono);z-index:1}
.filters{display:flex;flex-wrap:wrap;gap:10px 18px;align-items:center;margin:18px 0}
.fchips{display:flex;flex-wrap:wrap;gap:7px}
.fchip{border:1.5px solid var(--line2);background:var(--surface);border-radius:999px;padding:6px 13px;font-weight:700;font-size:.88rem;transition:all .2s}
.fchip:hover{border-color:var(--c,var(--blue))}
.fchip.on{background:var(--c,var(--ink));border-color:var(--c,var(--ink));color:#fff}
.egrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px;padding-bottom:20px}
.ecard{text-align:left;padding:18px;border-radius:var(--r);background:var(--surface);border:1px solid var(--line);box-shadow:var(--shadow);position:relative;overflow:hidden;transition:transform .25s,box-shadow .25s,border-color .25s;animation:rise .5s both;display:flex;flex-direction:column;gap:10px}
.ecard:hover{transform:translateY(-5px);box-shadow:var(--shadow2);border-color:var(--c)}
.ecard::before{content:'';position:absolute;left:0;top:0;height:4px;width:100%;background:var(--c);transform:scaleX(.18);transform-origin:left;transition:transform .35s}
.ecard:hover::before{transform:scaleX(1)}
.ecard .top{display:flex;align-items:center;justify-content:space-between;gap:8px}
.num{font:800 .95rem var(--mono);color:var(--c)}
.tag{font:700 .72rem var(--body);padding:3px 9px;border-radius:999px;background:color-mix(in srgb,var(--c) 13%,#fff);color:var(--c)}
.ecard h3{font-size:1.15rem}
.ecard p{color:var(--muted);font-size:.9rem;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.lvl{display:inline-flex;gap:3px;align-items:center;font-size:.75rem;font-weight:700;color:var(--muted)}
.lvl i{width:8px;height:8px;border-radius:50%;background:var(--line2)}
.lvl i.f{background:var(--c)}
.done-badge{position:absolute;right:14px;bottom:14px;width:28px;height:28px;border-radius:50%;background:var(--mint);color:#fff;display:grid;place-items:center;font-weight:800;font-size:.85rem;animation:pop .4s both}

/* ---------- workspace ---------- */
.crumbs{display:flex;align-items:center;gap:10px;padding-block:22px 12px;flex-wrap:wrap}
.crumbs .sp{flex:1}
.wtitle{display:flex;align-items:center;gap:14px;flex-wrap:wrap;margin-bottom:18px}
.wtitle h1{font-size:clamp(1.6rem,3.4vw,2.4rem);font-weight:800}
.bignum{width:52px;height:52px;border-radius:16px;background:var(--c);color:#fff;display:grid;place-items:center;font:800 1.3rem var(--mono);box-shadow:0 8px 18px color-mix(in srgb,var(--c) 40%,transparent)}
.ws{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.1fr);gap:18px;align-items:start}
.panel{padding:20px}
.panel h3{font-size:1.02rem;margin-bottom:10px;display:flex;align-items:center;gap:8px;text-transform:uppercase;letter-spacing:.08em;font-family:var(--body);font-weight:800;color:var(--muted);font-size:.78rem}
.story{color:var(--ink2);font-size:1.02rem}
.tasks{list-style:none;padding:0;margin:0;display:grid;gap:8px}
.tasks li{display:grid;grid-template-columns:24px 1fr;gap:10px;align-items:start;padding:10px 12px;border-radius:11px;background:var(--bg);border:1px solid var(--line);cursor:pointer;transition:all .2s}
.tasks li:hover{border-color:var(--blue)}
.tasks .bx{width:22px;height:22px;border-radius:7px;border:2px solid var(--line2);display:grid;place-items:center;color:#fff;font-size:.8rem;font-weight:800;background:#fff;transition:all .2s}
.tasks li.on{background:var(--mint-t);border-color:var(--mint)}
.tasks li.on .bx{background:var(--mint);border-color:var(--mint)}
.tasks li.on span{color:var(--ink2)}
.hintbox{display:grid;gap:8px;margin-top:6px}
.hint{padding:10px 14px;border-radius:11px;background:var(--sun-t);color:#5b4300;font-weight:500;animation:rise .4s both}
.exp{background:var(--code-bg);color:#8DF0C6;border-radius:12px;padding:12px 16px;font:500 .88rem/1.6 var(--mono);white-space:pre;overflow-x:auto;animation:rise .35s both}
.sep{height:1px;background:var(--line);margin:16px 0}
.editor{background:var(--code-bg);border-radius:14px;overflow:hidden;box-shadow:var(--shadow2)}
.ed-bar{display:flex;align-items:center;gap:8px;padding:9px 12px;background:rgba(255,255,255,.06);flex-wrap:wrap}
.ed-bar .fn{font:600 .78rem var(--mono);color:var(--code-dim);margin-right:auto;display:flex;align-items:center;gap:8px}
.ed-bar .btn{padding:7px 13px;font-size:.86rem;border-radius:9px}
.ed-bar .btn:not(.primary):not(.sun){background:rgba(255,255,255,.1);color:#DCE6FF;box-shadow:none}
.ed-bar .btn:not(.primary):not(.sun):hover{background:rgba(255,255,255,.18)}
.ed{display:flex;font:500 .9rem/1.65 var(--mono);min-height:280px;max-height:640px;overflow:auto}
.ed-g{padding:14px 8px 14px 12px;text-align:right;color:#55648C;user-select:none;background:rgba(0,0,0,.14);flex:0 0 auto;min-width:40px}
.ed-g div{height:1.65em}
.ed-g div.err{background:rgba(226,74,79,.4);color:#fff;border-radius:4px}
.ed-b{position:relative;flex:1;min-width:0}
.ed-hl,.ed-ta{margin:0;padding:14px 16px;font:inherit;line-height:inherit;white-space:pre;tab-size:4;border:0;letter-spacing:0;word-spacing:0}
.ed-hl{position:absolute;inset:0;color:var(--code-ink);pointer-events:none;overflow:hidden}
.ed-ta{position:relative;display:block;width:100%;background:transparent;color:transparent;caret-color:var(--sun);resize:none;outline:none;overflow-x:auto;overflow-y:hidden;min-height:100%}
.ed-ta::selection{background:rgba(255,200,58,.35)}
.tk-k{color:#FF9DB8}.tk-b{color:#7FD4FF}.tk-s{color:#B6F0A0}.tk-n{color:#FFCB7B}.tk-c{color:#7C8CB3;font-style:italic}.tk-f{color:#C9B6FF}
.outp{margin-top:14px;background:#fff;border:1px solid var(--line);border-radius:14px;overflow:hidden;box-shadow:var(--shadow)}
.outp-h{display:flex;gap:8px;align-items:center;padding:9px 14px;background:var(--bg2);font:800 .74rem var(--body);letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.outp-h .sp{flex:1}
.outp pre{margin:0;padding:12px 16px;font:500 .88rem/1.65 var(--mono);white-space:pre-wrap;word-break:break-word;min-height:72px;max-height:300px;overflow:auto}
.oline{display:block;animation:rise .28s both}
.oerr{color:var(--coral);font-weight:600}
.banner{display:flex;gap:12px;align-items:flex-start;padding:12px 16px;border-top:1px solid var(--line);animation:rise .4s both}
.banner.ok{background:var(--mint-t);color:#075E46}
.banner.no{background:var(--coral-t);color:#8a2226}
.banner.info{background:var(--blue-t);color:var(--blue-d)}
.banner .bi{width:26px;height:26px;border-radius:50%;flex:0 0 auto;display:grid;place-items:center;color:#fff;font-weight:800;font-size:.9rem}
.banner.ok .bi{background:var(--mint)}.banner.no .bi{background:var(--coral)}.banner.info .bi{background:var(--blue)}
.diff{font:500 .84rem/1.6 var(--mono);margin-top:6px;display:grid;gap:2px}
.diff div{padding:2px 8px;border-radius:6px;white-space:pre-wrap;word-break:break-all}
.diff .e{background:#c9f1e1}.diff .g{background:#ffd3d5}
/* solution area */
.sol{margin-top:22px}
.lock-card{padding:26px;text-align:center;background:linear-gradient(180deg,var(--surface),var(--bg2));border:2px dashed var(--line2);border-radius:var(--r)}
.lock-card h3{font-size:1.25rem;margin-bottom:6px}
.lock-card p{color:var(--muted);max-width:32em;margin:0 auto 16px}
.tabs{display:flex;gap:6px;overflow-x:auto;border-bottom:1px solid var(--line);padding:10px 14px 0;scrollbar-width:none}
.tabs::-webkit-scrollbar{display:none}
.tab{border:0;background:none;padding:10px 14px;font-weight:700;color:var(--muted);border-radius:10px 10px 0 0;position:relative;white-space:nowrap}
.tab.on{color:var(--blue-d);background:var(--blue-t)}
.tab.on::after{content:'';position:absolute;left:0;right:0;bottom:-1px;height:3px;background:var(--blue);border-radius:3px}
.tabbody{padding:22px;animation:rise .35s both}
.walk{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,1fr);gap:18px;align-items:start}
.wcode{background:var(--code-bg);border-radius:14px;padding:12px 0;overflow-x:auto;font:500 .88rem/1.7 var(--mono);color:var(--code-ink)}
.wl{display:flex;padding:0 14px 0 0;transition:background .35s,opacity .35s;white-space:pre;min-width:max-content}
.wl .n{flex:0 0 38px;text-align:right;padding-right:14px;color:#55648C;user-select:none}
.wl.act{background:rgba(255,200,58,.2);box-shadow:inset 3px 0 0 var(--sun)}
.wl.dim{opacity:.42}
.wcard{padding:18px;border-radius:14px;background:var(--sun-t);border:1px solid #F2DC90;min-height:170px}
.wcard .st{font:800 .74rem var(--body);letter-spacing:.1em;text-transform:uppercase;color:var(--sun-d);margin-bottom:8px}
.wcard p{color:#4b3800;animation:rise .4s both}
.wbar{display:flex;align-items:center;gap:8px;margin-top:12px;flex-wrap:wrap}
.dots{display:flex;gap:6px;margin-left:auto}
.dots i{width:9px;height:9px;border-radius:50%;background:var(--line2);transition:all .3s}
.dots i.on{background:var(--blue);transform:scale(1.35)}
.dots i.pas{background:var(--blue-t2)}
.codeblock{background:var(--code-bg);color:var(--code-ink);border-radius:14px;padding:16px 18px;font:500 .9rem/1.7 var(--mono);white-space:pre;overflow-x:auto}
.disc p{margin-bottom:14px;max-width:70ch;color:var(--ink2)}
.cards2{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:12px}
.mini{padding:14px 16px;border-radius:12px;background:var(--bg);border:1px solid var(--line);color:var(--ink2)}
.mini.w{background:var(--coral-t);border-color:#F4C7C9}
.mini.g{background:var(--mint-t);border-color:#B7E6D6}
.mini h4{font-size:.78rem;text-transform:uppercase;letter-spacing:.1em;margin-bottom:6px;font-family:var(--body);font-weight:800}
.mini.w h4{color:var(--coral)}.mini.g h4{color:var(--mint)}
/* ---------- quiz ---------- */
.quiz{max-width:820px;margin:0 auto}
.qhead{display:flex;align-items:center;gap:14px;margin-bottom:16px}
.bar{flex:1;height:10px;border-radius:99px;background:var(--line);overflow:hidden}
.bar i{display:block;height:100%;background:linear-gradient(90deg,var(--blue),var(--mint));border-radius:99px;transition:width .5s cubic-bezier(.2,.8,.2,1)}
.streak{font:800 .88rem var(--mono);color:var(--sun-d);background:var(--sun-t);padding:4px 10px;border-radius:999px}
.qcard{padding:26px}
.qcard h2{font-size:1.35rem;margin:10px 0 14px}
.opts{display:grid;gap:10px;margin-top:16px}
.opt{display:grid;grid-template-columns:34px 1fr;gap:12px;align-items:center;text-align:left;padding:13px 14px;border-radius:12px;border:2px solid var(--line);background:#fff;font-weight:600;transition:all .2s}
.opt:hover{border-color:var(--blue);transform:translateX(4px)}
.opt .l{width:30px;height:30px;border-radius:9px;background:var(--bg2);display:grid;place-items:center;font:800 .85rem var(--mono);color:var(--muted);transition:all .2s}
.opt.right{background:var(--mint-t);border-color:var(--mint);animation:pop .4s}
.opt.right .l{background:var(--mint);color:#fff}
.opt.wrong{background:var(--coral-t);border-color:var(--coral);animation:shake .45s}
.opt.wrong .l{background:var(--coral);color:#fff}
.opt.lock{pointer-events:none}
.opt.fade{opacity:.55}
.why{margin-top:16px;padding:14px 16px;border-radius:12px;background:var(--blue-t);color:var(--ink2);animation:rise .4s both}
.why b{color:var(--blue-d)}
.qfoot{display:flex;justify-content:flex-end;margin-top:16px}
.setup{padding:28px}
.res{padding:34px;text-align:center}
.bigring{--p:0;width:170px;height:170px;border-radius:50%;margin:0 auto 18px;background:conic-gradient(var(--mint) calc(var(--p)*1%),var(--line) 0);display:grid;place-items:center;transition:background 1s}
.bigring::before{content:'';grid-area:1/1;width:138px;height:138px;border-radius:50%;background:var(--surface)}
.bigring b{grid-area:1/1;z-index:1;font:800 2.2rem var(--display)}
.rev{text-align:left;margin-top:22px;display:grid;gap:10px}
.rev .mini{background:var(--coral-t);border-color:#F4C7C9}
.stats{display:flex;gap:12px;flex-wrap:wrap;margin:14px 0}
.stat{padding:10px 14px;border-radius:12px;background:var(--bg);border:1px solid var(--line);font-weight:700}
.stat small{display:block;color:var(--muted);font-weight:600}
.banner-warn{margin:14px 0;padding:12px 16px;border-radius:12px;background:var(--sun-t);color:#5b4300;font-weight:600}
/* confetti */
.cf{position:fixed;top:-12px;width:10px;height:14px;z-index:99;pointer-events:none;animation:fall linear forwards}
@keyframes fall{to{transform:translate(var(--dx),105vh) rotate(720deg);opacity:.9}}
.toast{position:fixed;left:50%;bottom:calc(24px + env(safe-area-inset-bottom,0px));transform:translateX(-50%);background:var(--ink);color:#fff;padding:11px 18px;border-radius:12px;font-weight:700;z-index:90;animation:rise .35s both;box-shadow:var(--shadow2)}

@media (max-width:900px){
  .hero-grid,.lab,.ws,.band,.walk{grid-template-columns:1fr}
  .pillars{grid-template-columns:1fr}
  .hero{padding-block:36px 24px}
  .demo{margin-top:8px}
  .float-tag.f1{right:6px}.float-tag.f2{left:0}
}
@media (max-width:560px){
  .two{grid-template-columns:1fr}
  .nav .wrap{gap:8px}
  .brand .bt{display:none}
  .lg{display:none}
  .links button{padding:8px 11px;font-size:.92rem}
  .egrid{grid-template-columns:1fr}
  .panel,.lab-main,.lab-side,.tabbody,.qcard{padding:16px}
  .ed{font-size:.82rem}
}
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important;scroll-behavior:auto!important}
}

/* ---------- v2 additions ---------- */
.live{display:inline-block;width:9px;height:9px;border-radius:50%;background:var(--mint);margin-right:8px;box-shadow:0 0 0 0 rgba(15,159,119,.5);animation:ping 2s infinite}
@keyframes ping{70%{box-shadow:0 0 0 10px rgba(15,159,119,0)}100%{box-shadow:0 0 0 0 rgba(15,159,119,0)}}
.hero{padding-block:84px 96px}
.hero::before{animation:gridmove 30s linear infinite}
@keyframes gridmove{to{background-position:26px 52px}}
.blob.b3{width:220px;height:220px;background:#C9F0E2;right:30%;bottom:-70px;animation-delay:-3s}
.orb{position:absolute;border-radius:50%;animation:bob 6s ease-in-out infinite}
.orb.o1{width:34px;height:34px;background:var(--sun);right:-14px;top:-14px}
.orb.o2{width:20px;height:20px;background:var(--blue);left:-10px;bottom:30px;animation-delay:-2s}
.orb.o3{width:14px;height:14px;background:var(--mint);right:44px;bottom:-16px;animation-delay:-4s}
.logo span{font:800 20px var(--display);line-height:1}
/* page-head decoration: every page has ambient motion */
.page-head{position:relative}
.decor{position:absolute;inset:-10px 0 0 0;pointer-events:none;overflow:hidden;z-index:0}
.decor span{position:absolute;font:800 1.5rem var(--mono);color:var(--blue);opacity:.13;animation:floaty 9s ease-in-out infinite}
.decor .g1{right:4%;top:10%}.decor .g2{right:14%;top:52%;animation-delay:-2s;color:var(--t-list)}.decor .g3{right:26%;top:14%;animation-delay:-4s;color:var(--t-tuple)}
.decor .g4{right:36%;top:60%;animation-delay:-6s;color:var(--t-cond)}.decor .g5{right:46%;top:8%;animation-delay:-3s;color:var(--t-dict)}.decor .g6{right:8%;top:70%;animation-delay:-5s;color:var(--t-range);font-size:2.2rem}.decor .g7{right:56%;top:50%;animation-delay:-7s;color:var(--t-set)}
@keyframes floaty{0%,100%{transform:translateY(0) rotate(-4deg)}50%{transform:translateY(-16px) rotate(6deg)}}
.page-head>*:not(.decor){position:relative;z-index:1}
.wtitle{position:relative}
.wtitle .decor{inset:-20px 0 -10px 0}.wtitle>*:not(.decor){position:relative;z-index:1}
.bignum{animation:ringpulse 3s ease-in-out infinite}
@keyframes ringpulse{0%,100%{box-shadow:0 8px 18px color-mix(in srgb,var(--c) 40%,transparent),0 0 0 0 color-mix(in srgb,var(--c) 30%,transparent)}50%{box-shadow:0 8px 18px color-mix(in srgb,var(--c) 40%,transparent),0 0 0 10px transparent}}
.ws>*{animation:rise .55s both}.ws>*:nth-child(2){animation-delay:.12s}
.qcard,.setup{animation:rise .5s both}
/* concept lab shell */
.labshell{display:grid;grid-template-columns:232px minmax(0,1fr);gap:20px;align-items:start;margin-top:8px}
.labnav{position:sticky;top:78px;padding:10px;display:flex;flex-direction:column;gap:4px}
.ln-item{display:flex;align-items:center;gap:12px;text-align:left;border:0;background:none;padding:10px 12px;border-radius:12px;font-weight:700;color:var(--ink2);position:relative;transition:background .2s,transform .2s,color .2s;animation:slidein .5s both}
@keyframes slidein{from{opacity:0;transform:translateX(-14px)}to{opacity:1;transform:none}}
.ln-item i{font:800 .8rem var(--mono);font-style:normal;min-width:44px;text-align:center;padding:4px 6px;border-radius:8px;background:color-mix(in srgb,var(--c) 14%,#fff);color:var(--c);transition:all .2s}
.ln-item:hover{background:var(--bg2);transform:translateX(3px)}
.ln-item.on{background:var(--c);color:#fff;box-shadow:0 8px 18px color-mix(in srgb,var(--c) 35%,transparent)}
.ln-item.on i{background:rgba(255,255,255,.22);color:#fff}
.labcol{display:grid;gap:18px;min-width:0}
.labcol .lab-main{animation:rise .5s both}
.labcol .lab-side ul{columns:2;column-gap:28px}
.labcol .lab-side li{break-inside:avoid}
/* data types lab */
.samples{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:12px}
.sample{border:1.5px solid var(--line2);background:#fff;border-radius:11px;padding:8px 12px;transition:all .2s}
.sample code{background:none;color:var(--ink);padding:0;font-weight:700;font-size:.92rem}
.sample:hover{border-color:var(--c);transform:translateY(-3px)}
.sample.on{background:var(--c);border-color:var(--c);transform:translateY(-3px);box-shadow:0 8px 16px color-mix(in srgb,var(--c) 35%,transparent)}
.sample.on code{color:#fff}
.tdetail{display:grid;grid-template-columns:auto auto 1fr;gap:10px 14px;align-items:center;background:var(--bg);border:1px solid var(--line);border-radius:14px;padding:16px}
.tcode{font:700 1.05rem var(--mono);background:var(--code-bg);color:var(--code-ink);padding:9px 14px;border-radius:10px;max-width:100%;overflow-x:auto;white-space:pre}
.tcode b{color:#FFCB7B}
.tarrow{font-weight:800;color:var(--muted);animation:nudge 1.6s ease-in-out infinite}
@keyframes nudge{50%{transform:translateX(6px)}}
.tbadge{font:800 1.1rem var(--mono);color:var(--c);background:color-mix(in srgb,var(--c) 12%,#fff);padding:8px 14px;border-radius:10px;border:2px solid var(--c);animation:pop .45s both}
.tinfo{grid-column:1/-1;display:grid;gap:10px}
.props{display:flex;flex-wrap:wrap;gap:8px}
.prop{font:700 .82rem var(--body);background:#fff;border:1px solid var(--line2);border-radius:999px;padding:4px 12px}
.yn{margin-left:6px;padding:1px 8px;border-radius:999px;font-size:.75rem}
.yn.y{background:var(--mint-t);color:var(--mint)}.yn.n{background:var(--coral-t);color:var(--coral)}.yn.m{background:var(--bg2);color:var(--muted)}
.tops small{display:block;font:700 .72rem var(--body);text-transform:uppercase;letter-spacing:.1em;color:var(--muted);margin-bottom:4px}
.tops code{white-space:pre-wrap}
.sep2{height:1px;background:var(--line);margin:22px 0}
.arith{display:grid;gap:6px}
.arow{display:grid;grid-template-columns:96px 1fr auto;gap:12px;align-items:center;padding:8px 14px;border-radius:10px;background:#fff;border:1px solid var(--line);animation:pop .3s both}
.arow code{background:none;color:var(--ink);font-weight:700;padding:0}
.arow.bad{grid-template-columns:96px 1fr;background:var(--coral-t);border-color:#F4C7C9}
.arow.bad .ares{color:var(--coral)}
.ares{font:800 1.05rem var(--mono)}
.atype{font:800 .74rem var(--mono);padding:3px 10px;border-radius:999px}
.atype.int{background:var(--blue-t);color:var(--blue-d)}.atype.float{background:var(--sun-t);color:#7a5600}
@media (max-width:900px){
  .labshell{grid-template-columns:1fr}
  .labnav{position:static;flex-direction:row;overflow-x:auto;scrollbar-width:none}
  .ln-item{flex:0 0 auto}.ln-item span{white-space:nowrap}
  .labcol .lab-side ul{columns:1}
  .tdetail{grid-template-columns:1fr}.tarrow{display:none}
}
.labshell>*,.labcol>*{min-width:0}
.lab-main{overflow:hidden}

/* ---------- v3: new labs ---------- */
.ln-group{font:800 .68rem var(--body);letter-spacing:.12em;text-transform:uppercase;color:var(--muted);padding:10px 12px 2px}
.tlrow{display:flex;gap:16px;align-items:center;margin-top:12px;flex-wrap:wrap}
.tlight{background:#1b2540;border-radius:16px;padding:10px;display:flex;flex-direction:column;gap:8px}
.tlight i{width:34px;height:34px;border-radius:50%;background:#33405f;transition:all .3s}
.tlight i.r.on{background:#ff4b55;box-shadow:0 0 22px #ff4b55}.tlight i.y.on{background:#ffc83a;box-shadow:0 0 22px #ffc83a}.tlight i.g.on{background:#2fd08f;box-shadow:0 0 22px #2fd08f}
.quad{position:relative;padding:0 0 22px 0}.qx,.qy{font:700 .72rem var(--body);letter-spacing:.06em;text-transform:uppercase;color:var(--muted);text-align:center;margin-bottom:6px}.qy{margin:6px 0 0}
.qgrid{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.qcell{border:1.5px solid var(--line);border-radius:14px;padding:12px;background:#fff;min-height:110px;transition:all .3s;display:flex;flex-direction:column;gap:2px}
.qcell b{font-size:.95rem}.qcell small{color:var(--muted);font-size:.8rem}.qcell.on{border-color:var(--blue);background:var(--blue-t);box-shadow:0 8px 20px rgba(42,91,215,.16);transform:translateY(-2px)}
.qdots{display:flex;gap:6px;flex-wrap:wrap;margin-top:auto;padding-top:8px}
.qdot{border:1.5px solid var(--line2);background:#fff;border-radius:999px;padding:4px 12px;font:700 .82rem var(--mono);transition:all .2s}.qdot:hover{transform:translateY(-2px)}.qdot.on{background:var(--blue);border-color:var(--blue);color:#fff}
.bind{display:flex;gap:12px;align-items:center;flex-wrap:wrap;min-height:70px}
.bcol{display:flex;flex-direction:column;gap:8px}
.bname{font:800 1rem var(--mono);background:var(--blue-t);color:var(--blue-d);border:2px solid var(--blue);border-radius:10px;padding:8px 16px;min-width:54px;text-align:center}
.barrow{font:800 1.3rem var(--mono);color:var(--muted);height:44px;display:grid;place-items:center}
.bobj{background:var(--sun-t);border:2px solid var(--sun-d);border-radius:12px;padding:6px 14px;min-width:90px;height:44px;display:flex;flex-direction:column;justify-content:center;box-sizing:border-box}
.bobj b{font:800 .95rem/1 var(--mono);color:#5b4300}.bobj small{font:700 .66rem var(--body);text-transform:uppercase;letter-spacing:.08em;color:#8a6a10}
.bname{height:44px;box-sizing:border-box;display:grid;place-items:center;padding:0 16px}
.anat .ap{cursor:pointer;border-radius:5px;transition:background .2s,box-shadow .2s;border-bottom:2px dotted rgba(255,255,255,.35)}
.anat .ap:hover{background:rgba(255,255,255,.14)}.anat .ap.on{background:rgba(255,200,58,.3);box-shadow:0 0 0 2px var(--sun)}
.mtable{display:flex;flex-direction:column;gap:4px;margin-top:8px;overflow-x:auto}
.mrow{display:grid;grid-template-columns:minmax(150px,1.6fr) repeat(5,minmax(70px,1fr));gap:6px;align-items:center;text-align:left;border:1.5px solid var(--line);background:#fff;border-radius:11px;padding:8px 10px;font:inherit;transition:all .2s;min-width:560px}
.mrow small{display:block;font:600 .74rem var(--mono);color:var(--muted)}
button.mrow:hover{transform:translateX(3px);border-color:var(--line2)}.mrow.on{border-color:var(--blue);background:var(--blue-t);box-shadow:0 6px 16px rgba(42,91,215,.15)}
.mhead{border:0;background:none;font:800 .7rem var(--body);text-transform:uppercase;letter-spacing:.08em;color:var(--muted);padding:2px 10px}
.mm{font:700 .78rem var(--body);text-align:center;border-radius:999px;padding:3px 8px}.mm.y{background:var(--mint-t,#DDF5EA);color:#0a6b4d}.mm.n{background:var(--coral-t,#FDE3E4);color:#a1282d}
.mgrid{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:14px}.mgrid small{display:block;font:800 .7rem var(--body);text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin-bottom:5px}
.mres{display:flex;gap:10px;align-items:flex-start;border-radius:12px;padding:10px 12px;font-size:.85rem;min-width:0;overflow-wrap:anywhere}
.mres i{font-style:normal;font-weight:800;width:22px;height:22px;border-radius:50%;display:grid;place-items:center;flex:none;color:#fff}
.mres.ok{background:#E6F7EF}.mres.ok i{background:#0F9F77}.mres.bad{background:#FDECEC}.mres.bad i{background:#E24A4F}
.mres code{font:600 .8rem var(--mono);background:none;padding:0;color:var(--ink)}
.pipe{display:flex;gap:8px;align-items:stretch;flex-wrap:wrap}
.pstage{flex:1 1 130px;border:2px solid var(--line);border-radius:14px;padding:10px 12px;background:#fff;transition:all .35s;min-width:0}
.pstage b{display:block}.pstage small{color:var(--muted);font-size:.75rem;font-weight:700}.pstage pre{font:600 .72rem/1.5 var(--mono);margin:8px 0 0;color:var(--ink2);white-space:pre-wrap;overflow-wrap:anywhere}
.pstage.lit{border-color:var(--sun-d);background:var(--sun-t);transform:translateY(-4px);box-shadow:0 12px 22px rgba(255,200,58,.4)}.pstage.done{border-color:var(--mint,#0F9F77);background:#F1FBF6}.pstage.skip{opacity:.4;border-style:dashed}
.parrow{align-self:center;font:800 1.3rem var(--mono);color:var(--muted)}
.cachebox{margin-top:12px;display:flex;gap:10px;align-items:center;border:2px dashed var(--line2);border-radius:12px;padding:8px 12px;font:600 .82rem var(--mono);color:var(--muted);transition:all .3s;overflow-wrap:anywhere}
.cachebox i{font:800 .75rem var(--mono);font-style:normal;background:var(--bg2);border-radius:7px;padding:3px 7px}.cachebox.on{border-style:solid;border-color:#0F9F77;color:#0a6b4d;background:#F1FBF6}.cachebox.on i{background:#0F9F77;color:#fff}
.pathlist{display:flex;flex-direction:column;gap:6px;margin-top:10px}
.pdir{display:flex;gap:10px;align-items:center;border:1.5px solid var(--line);border-radius:10px;padding:7px 12px;font:600 .85rem var(--mono);background:#fff;transition:all .25s}
.pdir i{font-style:normal;background:var(--bg2);border-radius:6px;width:22px;height:22px;display:grid;place-items:center;font-size:.72rem}
.pdir.look{background:var(--sun-t);border-color:var(--sun-d);transform:translateX(6px)}.pdir.found{background:#E6F7EF;border-color:#0F9F77}
.tree{background:var(--code-bg);color:var(--code-ink);border-radius:12px;padding:10px 6px;font:600 .85rem var(--mono);overflow-x:auto}
.tn{padding:5px 8px;border-radius:7px;white-space:nowrap;transition:all .3s;margin:1px 0}.tn.i{color:#FFC83A}.tn.load{background:rgba(47,208,143,.25);box-shadow:inset 3px 0 0 #2fd08f;transform:translateX(4px)}
.flow,.stepper{display:flex;gap:6px;flex-wrap:wrap;align-items:center;margin-top:12px}
.fstep{border:2px solid var(--line);border-radius:12px;padding:8px 12px;font-weight:700;font-size:.85rem;background:#fff;transition:all .3s;flex:1 1 120px}.fstep.lit{background:#E6F7EF;border-color:#0F9F77}.fstep.slow.lit{background:var(--sun-t);border-color:var(--sun-d)}
.vpkg{border-radius:12px;padding:12px 14px;font:800 1rem var(--mono)}.vpkg.ok{background:#E6F7EF;color:#0a6b4d}.vpkg.bad{background:#FDECEC;color:#a1282d}.vpkg small{display:block;font:600 .75rem var(--body)}
.stepper{flex-direction:column;align-items:stretch;gap:6px}.stp{display:flex;gap:12px;align-items:center;border:1.5px solid var(--line);border-radius:11px;padding:8px 12px;background:#fff;transition:all .25s;font-size:.9rem}
.stp i{font:800 .8rem var(--mono);font-style:normal;background:var(--bg2);width:24px;height:24px;border-radius:50%;display:grid;place-items:center;flex:none}
.stp.cur{border-color:var(--blue);background:var(--blue-t);transform:translateX(5px)}.stp.done{opacity:.55}.stp.done i{background:#0F9F77;color:#fff}
.term{min-height:120px}
@media (max-width:700px){.mgrid{grid-template-columns:1fr}}

/* ---------- v3: landing sections ---------- */
.brand .bt{display:flex;flex-direction:column;line-height:1.05}.brand .bt small{font:700 .62rem var(--body);letter-spacing:.14em;text-transform:uppercase;color:var(--blue);margin-top:2px}
.sect{padding-block:44px 8px}.sect-head{max-width:640px;margin-bottom:22px}.sect-head h2{font-size:clamp(1.7rem,3.6vw,2.4rem);margin:6px 0 8px}.sect-head p{color:var(--muted);margin:0}
.pg-grid{display:grid;grid-template-columns:1.25fr .75fr;gap:18px;align-items:stretch}.pg-grid>*{min-width:0}
.pg-ed .ed{min-height:170px}.pgchip.on{background:var(--sun)!important;color:#3d2c00!important}
.pg-out{background:#fff;border:1.5px solid var(--line);border-radius:14px;padding:14px 16px;display:flex;flex-direction:column;box-shadow:var(--shadow)}
.pg-head{font:800 .72rem var(--body);letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin-bottom:8px}
.pgout{margin:0;flex:1;min-height:120px;background:var(--code-bg);color:#8DF0C6;border-radius:10px;padding:12px 14px;font:600 .9rem/1.6 var(--mono);white-space:pre-wrap;overflow-wrap:anywhere}.pgout.err{color:#FF9DA1}
.flips{display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:16px;perspective:1000px}
.flip{border:0;background:none;padding:0;height:190px;text-align:left;animation:rise .6s both;cursor:pointer;font:inherit;color:inherit}
.fin{display:block;position:relative;width:100%;height:100%;transition:transform .7s cubic-bezier(.3,1.2,.4,1);transform-style:preserve-3d}
.flip.on .fin{transform:rotateY(180deg)}.flip:hover .fin{transform:translateY(-4px)}.flip.on:hover .fin{transform:rotateY(180deg) translateY(-4px)}
.ff,.fb{position:absolute;inset:0;border-radius:16px;padding:16px;backface-visibility:hidden;-webkit-backface-visibility:hidden;display:flex;flex-direction:column;box-shadow:var(--shadow);overflow:hidden}
.ff{background:var(--code-bg);color:var(--code-ink)}.ff small,.fb small{font:800 .68rem var(--body);letter-spacing:.12em;text-transform:uppercase;opacity:.7}
.ff pre{margin:auto 0;font:600 .92rem/1.5 var(--mono);white-space:pre-wrap;overflow-wrap:anywhere;color:#fff}.ff em{font:700 .78rem var(--body);color:var(--sun);font-style:normal}
.fb{background:linear-gradient(150deg,var(--sun),#FFE08A);color:#3d2c00;transform:rotateY(180deg)}.fb b{font:800 1.5rem var(--mono);margin:10px 0 6px;overflow-wrap:anywhere}.fb p{margin:0;font-size:.85rem;font-weight:600}
.foot{margin-top:60px;background:linear-gradient(180deg,transparent,var(--blue-t) 60%);padding:44px 0 30px;position:relative;overflow:hidden}
.foot-in{display:flex;align-items:center;gap:24px;flex-wrap:wrap;position:relative}.foot-brand{display:flex;gap:12px;align-items:center;font-family:var(--display)}.foot-brand b{display:block;font-size:1.2rem}.foot-brand small{color:var(--blue);font:700 .7rem var(--body);letter-spacing:.14em;text-transform:uppercase}
.foot p{margin:0;color:var(--muted);font-weight:600}
.foot-mark{position:absolute;right:2%;top:-40px;font:800 9rem/1 var(--display);color:var(--blue);opacity:.08;animation:floaty 7s ease-in-out infinite;pointer-events:none}
@media (max-width:820px){.pg-grid{grid-template-columns:1fr}}
@media (prefers-reduced-motion:reduce){.fin{transition:none}.foot-mark{animation:none}}

.lab-desc{padding:22px 26px}.lab-desc h4{font-size:1.02rem;margin:18px 0 4px;color:var(--ink)}.lab-desc p{margin:0;color:var(--ink2);line-height:1.7;max-width:70ch}
@media (max-width:700px){.lab-desc{padding:16px}}

.lab-intro{max-width:78ch;margin-top:10px}.lab-intro p{color:var(--ink2);line-height:1.7;margin:0 0 10px}

.labshell{margin-top:38px}.labright{min-width:0}.labright .page-head{padding-block:0 18px}.labnav{top:78px}

/* ---- account (Supabase) ---- */
.acct{margin-left:4px}.acct-btn{display:flex;align-items:center;gap:6px;border:1.5px solid var(--line2);background:#fff;border-radius:999px;padding:7px 12px;font-weight:700;color:var(--ink2);transition:all .2s}
.acct-btn:hover{transform:translateY(-1px);border-color:var(--blue);color:var(--blue)}.acct-btn.on{background:var(--blue);border-color:var(--blue);color:#fff}
.acct-modal{position:fixed;inset:0;background:rgba(14,26,51,.45);display:grid;place-items:center;z-index:100;padding:16px;animation:rise .25s both}
.acct-card{background:#fff;border-radius:18px;padding:24px;max-width:420px;width:100%;box-shadow:var(--shadow2)}.acct-card h3{margin:0 0 8px}.acct-card p{color:var(--muted);margin:0 0 12px}
.acct-card form{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:8px}.acct-card input{flex:1 1 200px;font:600 1rem var(--body);padding:10px 12px;border:1.5px solid var(--line2);border-radius:10px;min-width:0}
.acct-msg{min-height:1.4em;font-weight:600;color:var(--ink2)!important}
@media (max-width:560px){.acct-btn .lg{display:none}.acct-btn{padding:8px}}
.oauth{display:flex;flex-direction:column;gap:8px;margin-bottom:12px}.oauth .btn{width:100%;justify-content:center}.acct-or{font-size:.9rem}
.acct-guest{border-top:1px solid var(--line);padding-top:14px;margin-top:6px;display:flex;flex-direction:column;gap:6px}.acct-guest .btn{width:100%;justify-content:center}.acct-guest small{color:var(--muted)}
.oauth{margin-top:14px}.acct-card form{margin-top:4px}